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Solar radiation and its hygienic importance




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2. /Module1. General questions of Hygiene and Ecology/Lectures/Health and Environment.rtf
3. /Module1. General questions of Hygiene and Ecology/Lectures/Introduction to hygine.rtf
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16. /Module1. General questions of Hygiene and Ecology/Practical studies/Illumination/Natur. ill. doc.doc
17. /Module1. General questions of Hygiene and Ecology/Practical studies/Illumination/SOLAR RADIATION AND ITS HYGIENIC IMPORTANCE.doc
18. /Module1. General questions of Hygiene and Ecology/Practical studies/Illumination/Topic 04.doc
19. /Module1. General questions of Hygiene and Ecology/Practical studies/Illumination/Topic 05.doc
20. /Module1. General questions of Hygiene and Ecology/Practical studies/Illumination/illuminatiom artif. doc.doc
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24. /Module1. General questions of Hygiene and Ecology/Practical studies/Microclimate ass/RESEARCH OF THE FACTOR OF INFRA-RED RADIATION.doc
25. /Module1. General questions of Hygiene and Ecology/Practical studies/Microclimate ass/Topic 06.doc
26. /Module1. General questions of Hygiene and Ecology/Practical studies/Microclimate ass/Topic 07.doc
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31. /Module1. General questions of Hygiene and Ecology/Practical studies/Water ass/Mannual 1.doc
32. /Module1. General questions of Hygiene and Ecology/Practical studies/Water ass/Mannual 2.doc
33. /Module1. General questions of Hygiene and Ecology/Practical studies/Work hardness/hardness and intencity 2.rtf
34. /Module1. General questions of Hygiene and Ecology/Practical studies/ultraviolate/manual.rtf
Лекция на тему: Здоровье детей и подростков как гигиеническая проблема. Физиолого-гигиенические
Лекция на тему: «Окружающая среда и здоровье»
Health (who) it is a state of complete physical, mental and social well-being, and not merely the absence of diseases or infirmity
Lecture “ Nutrition as a health factor”
Лекция на тему «Труд и здоровье»
Вода и здоровье” ( лекция для англоязычных студентов 3- го курса ммф ) Лекцию подготовил доцент кафедры гигиены и экологии Клименко А. И
Theme Hygienic assessment of the complex microclimate influence to the human organism
Тopic 8 methods of hygienic assessment of complex effects of the microclimate on the human heat exchange
Theme: methods of hygienic assessment of the dust and chemical admixtures level in atmospheric air
The methods of air sampling
Methods of determination and hygienic assessment of the dust content in the air
Theme: Food poisoning prevention
Theme: the complex assesment of individual health of children and adolescents
Hygienic assessment of conditions and organization of education in comprehensive school
Hygienic estimate of insolation regimen, daylight and candlelight of hospital apartments
Theme: Methods of hygienic investigations and assessment natural illumination and insolating regime in premises Purpose
Solar radiation and its hygienic importance
Topic №4 methods of determination and hygienic assessment of natural lighting in different premises
Topic №5 methods of determination and hygienic assessment of artificial illumination in different premises
Theme: Methods of the hygienic investigation and assessment of the artificial illumination in premises Purpose
The adequacy of the individual nutrition study according to the daily energy intake
Hygienic importance of the air movement in premises
Determination of atmospheric pressure
Research of the factor of infra-red radiation
Тopic №6 Method of determination of temperature and humidity conditions indoors and their hygienic assessment
Method of determination and hygienic assessment of the air movement direction and speed
Methods of determination of со
Microclimate of premises
Theme: Hygienic assessment of the noise and vibration as occupational hazards
Topic №18 method of hygienic assessment of soil according to sanitary examination of the land parcel and results of laboratory analysis of samples
The hygienic estimation of quality of potable water according to inspection and to results of the laboratory analysis
Umanskiy, А. N. Bessmertniy hygienic regulation of water quality. Basic methods of water treatment
Theme: Hygienic assessment of occupational hardness and intensity
Theme: Methods of determination of the ultraviolet radiation intensity as such as preventive dose of it’s irradiation and use it for diseases prevention and air disinfection in premises

SOLAR RADIATION AND ITS HYGIENIC IMPORTANCE

Solar radiation understands an integrated flow, let out by the sun, of radiation. Solar radiation is a light source and heat, all organic life on ground is obliged by the existence to it. From the physical point of view the solar energy represents a flow of electromagnetic radiations described in various length of a wave. The spectral structure of the sun changes in a wide range from long waves up to waves with very small size.

Owing to absorption, reflection and dispersion of rays energy in world space on a surface of ground the solar spectrum is limited, is especial in its short-wave part.

If on border of a terrestrial atmosphere the ultra-violet part of a solar spectrum makes 5 % seen part - 52 %, infra-red part - 43 %, at a surface of ground structure of solar radiation other: the ultra-violet part is equaled 1 % seen - 40 %, and infra-red part - 69 %.

The quantitative characteristic of solar radiation is defined by a voltage of radiation in calories a 1 minute on 1 см2 of a surface located perpendicularly to a source of radiation. As the standard of intensity of solar radiation use size solar constant, measured on border of an atmosphere, where the factors promoting reflection, dispersion and absorption of solar beams, are shown to a minimum.

In the European part USSR solar constant is equaled 1,88 cal/sm2/min. Within one year it varies and makes on January 1 -3,4 % and on July 1 +3,5 % from average size.

At a surface of ground the voltage of solar radiation always is less, than size solar constant. It is explained as unequal height of an arrangement of the sun above horizon, and various degree of cleanliness of atmospheric air, large variety of weather conditions, presence of clouds, deposits etc. So, the intensity of solar radiation at a surface of ground at height of an arrangement of the sun above horizon in 90° will be more, than at an arrangement of the sun is direct above horizon, as in this case weight of an atmosphere, which there pass solar beams, increases in 35 times in comparison with weight of an atmosphere at height of an arrangement of the sun above horizon in 90°. At rise on height weight of an atmosphere, which there passes solar beams, decrease, and therefore increase intensity of solar radiation. For example, at height 1000 m the intensity of solar radiation make 1,17 cal/sm2/min; At height 2000 m it increase up to 1,26 cal/sm2/min and at height 3000 m - up to 1,38 cal/sm2/min.

Depending on height of an arrangement of the sun above horizon the parity of direct and absent-minded solar radiation changes, that has essential meaning in an estimation of its biological action.

Solar radiation is the powerful medical preventive factor. It affects all physiological processes in organism, changing an exchange of substances, general tonus and serviceability.

Ultra-violet part of a solar spectrum

Most active in the biological attitude is the ultra-violet part of a solar spectrum, which at a surface of ground is submitted by a flow of waves in a range from 290 up to 466 nm. The intensity of ultra-violet radiation at a surface of ground is changeable and depends on breadth of district, season, condition of weather, degree of a transparency of an atmosphere. At cloudy weather the intensity of ultra-violet radiation at a surface of ground can be reduced on 80 %; at the expense of a dust content of atmospheric air this loss makes from 11 up to 50 %.

The ultra-violet beams, getting on a skin with its extensive reception surface, not only cause local shifts in colloidal condition cellular and fabric fibers, but also by a reflection way influence on organism. Under action of ultra-violet beams in a skin owing to fermented splitting of denatured and coagula albumens the products of albumen molecules splitting such as histamine, holynum are formed etc. The occurrence of similar biologically active substances is connected to some term after an irradiation, which speaks about photochemical action of ultra-violet beams.

Being not specific stimulator of physiological functions, the ultra-violet beams render beneficial effect on albumen, fatty, carbohydrate and mineral exchanges. Thus the tissue breath skin changes, the activity of reticuloendotelial and blood creating systems amplifies. The irradiation by ultra-violet beams causes shifts also in them immune condition of organism, promotes amplification of reaction of phagocytes, that results in increase of protective forces. The mechanism of physiological action of ultra-violet beams is combined and before the present time completely is not investigated. The numerous theories explain biological action of ultra-violet beams from various positions: from the point of view of the amplified development of similar histamine substances, activization of sulfhydral groups of fibers, stimulation of hypophis-adrenal system work.

Ultra-violet radiation renders not only about biological influence on all systems and bodies, but also specific action peculiar to a certain range of waves. It is known, that ultra-violet radiation with a range of waves from 400 up to 320 nm causes action of sunburn (area A), with a range of waves from 320 up to 275 nm - antirachital and weak bactericidal action (area B), and short-wave ultra-violet radiation with a range of waves from 275 up to 180 nm (area C) renders damaging action on a biological fabric. On a surface of ground the biological objects are not exposed to pernicious action of short-wave ultra-violet radiation, as in the top layers of an atmosphere there is a dispersion and absorption of waves to length less than 290 nm.

From all spectrum of ultra-violet radiation the surface of ground the greatest densities has ultra-violet radiation rendering action of sunburn. Ultra-violet eritema has a number of features in comparison with eritema, received from infra-red radiation. So, ultra-violet eritema has the strictly outlined contours limiting a site of influence of ultra-violet beams, arises after some incubation period and, as a rule, passes in sunburn. Eritema from infra-red thermal radiation occurs at once after its influence, has dim edges and in sunburn does not pass.

Is marked, that short-wave ultra-violet radiation causes eritema through shorter interval of time, than with a long wave.

The mechanism of occurrence ultra-violet eritema is insufficiently investigated. Believe, that it is connected with expanding vessels effect of histamine and similar histamine substances formed at a ultra-violet irradiation.

Now there are facts showing of a significant role of the central nervous system in development ultra-violet eritema. So, at infringement of conductivity of periphery nerves or after introduction of Novocain eritema on the given site of a skin weak or absolutely is absent.

Ultra-violet radiation in a range of waves from 320 up to 275 nm renders specific antirachital action that is shown in participation of ultra-violet radiation of this range in synthesis of vitamin D. The formation of vitamin D occurs by a photochemical way from vitamin D. This reaction carries out both on a surface of a skin, and in deeper layers in crates of a horn layer. At insufficient influence of ultra-violet beams of antirachital spectrum suffer an P - Ca exchange, nervous system, parenchymal bodies and blood-creating system, are reduced an oxide processes, the resistance of capillaries is broken, the serviceability and a resistance by cold diseases decreases. At children arises rachitis with the certain clinical displays. At the adult the infringement of P - Ca exchange on ground of hypovitaminosis D is expressed in bad accretion of bones at crises, easing of the ligament device of joints, in fast destruction of enamel of teeth. As it was specified above, ultra-violet radiation of an antirachital spectrum of action concerns to short-wave radiation, owing to what is easily absorbed and dissipate in conditions intensive dusting of atmospheric air.

In this connection the inhabitants of industrial cities, where atmospheric air becomes soiled by emissions of the industrial enterprises, test «ultra-violet hunger».The insufficiency of natural ultra-violet radiation is tested also by the inhabitants of Distant North, working coal industry, persons working in dark premises, etc. For updating insufficiency of a natural solar irradiation there was a necessity of an additional irradiation of these quotas of the people by artificial sources of ultra-violet radiation. It is carried out or in special photaries, or by a combination of lighting lamps with lamps giving radiation in a spectrum, close to natural ultra-violet radiation («ultra-violet illumination»). Most perspective and practically real is the way of enrichment of a light flow of lighting installations eritemal by a component.

The numerous researches on a preventive irradiation of the population of Distant North, workers of a coal and mountain industry, working shops without windows and other quota speak about salutary influence of an artificial ultra-violet irradiation on a line of physiological functions of organism and serviceability. The preventive application of ultra-violet beams improves state of health, raises resistance to cold and infectious diseases, increase serviceability.

The insufficiency of ultra-violet radiation not only renders adverse action on health of the man, but also influences processes of photosynthesis of plants. At cereals it results in deterioration of chemical structure of grains shown in reduction of the contents of fiber and increase of quantity of carbohydrates that reduces food value of a grain and brings known economic damage.

The large biological meaning has bactericidal effect of ultra-violet beams. Under influence of a natural ultra-violet irradiation of a bactericidal spectrum occurs a sanation of air environment, water, ground. Bactericidal effect have the beams with short length from 275-180 nm, the maximum of this effect comes on waves in a range from 253,7 up to 265,4 nm. Poorly bactericidal action is rendered by solar radiation in a range of waves from 280 up to 310 nm.

The efficiency of bactericidal action of ultra-violet beams reaching a surface of ground, reduced, as the range of waves of ultra-violet radiation of this kind of action is limited to waves of length 290-291 nm.

Under influence of a ultra-violet irradiation in a body of bacteria there are photochemical processes, which result in colloidal-chemical changes attracting behind self a destruction changes and destruction of a bacterium.

Is marked, that the different groups of a bacterium have various sensitivity to a ultra-violet irradiation at identical intensity of radiation and same range of waves. An intestinal stick (E. coli) and staphylococcus (Staphylococcus pyogenes) perish at a ultra-violet irradiation of bactericidal spectrum within 45 minutes, and activator of a typhus (Salmonella typhosa) - within 60 minutes. The bactericidal effect of ultra-violet radiation is used with the practical purposes. For this purpose apply bactericidal lamps giving a flow of rays of bactericidal spectrum, as a rule, with shorter length of a wave, than in a natural solar spectrum. Thus will be carried out a sanation of air environment in operational, microbiological boxings, premises for preparation of sterile medicines, environments etc. Bactericidal lamps can be applied for disinfection of milk, yeast, nonalcoholic drinks, that increase terms of a storage of products and their freshness.

The bactericidal action of artificial ultra-violet radiation is used also for disinfection of drinking water, that alongside with high efficiency of disinfection (99,8 %) there is a line of positive properties. Thus do not change a property of water, the extraneous chemical substances are not brought in to it.

However action of ultra-violet radiation on organism and external environment is not limited to beneficial effect. It is known, that the intensive solar irradiation results in development expressed eritema that is accompanied by increase of temperature of a body, headaches and general bad state of health. In heavy cases is possible a dermatitis with formation of bullas.

The most often defeat of an eye at influence of ultra-violet beams is photoophtalmia. In these cases arise a hyperemia and has swelled of conjunctiva, occur blefarospasm, current of tears and fear of light. The similar defeats are most often at reflection of beams of the sun from a surface of snow in the Arctic and high-mountainous areas («snow blindness»).

In the literature the cases of dermatitis are described at a ultra-violet irradiation at the persons simultaneously subjecting to action of a dust coal. Similar, the phenomena connected to raise sensitivity to influence of ultra-violet beams, have received the name sensibilisations. The raised sensitivity to ultra-violet beams happens at the patients with leaden intoxication, at children who have transferred measles, etc.

For last years in the literature the question on the raised frequency of occurrence of a crawfish of a skin at the persons constantly exposed to an intensive solar irradiation is discussed. On the data of A.V. Chaklin, the crawfish of a skin in southern areas makes 20-22 % of all forms of a crawfish (in northern areas 4-7 %).

The cases of a crawfish of a skin at the manufacturers of a grapes Bordeaux with a primary defeat of hands and person are described, that explain by a constant and intensive solar irradiation of open parts of a body. There were attempts to solve the problem on influence of an intensive ultra-violet irradiation on frequency of occurrence of a crawfish of a skin in experiment. However this question requires the further study.

Infra-red radiation

Alongside with ultra-violet radiation structure of a solar spectrum includes infra-red radiation, which renders on organism thermal influence.

On biological activity the infra-red beams divide on short-wave with a range of waves from 760 up to 1400 nm and long waves with a range of waves from 1500 up to 25 000 nm. The influence of infra-red beams on organism is appreciably defined by a degree of their absorption by a skin.

The absorption of infra-red beams by a skin defines in length of a wave. The beams with length of a wave from 1500 up to 3000 nm are absorbed by a superficial layer of a skin, the beams with length of a wave 1000 nm pass through epidermis; shorter infra-red beams reach fatty layers which are taking place under a skin. Being immersed less deeply, the long waves of infra-red radiation cause burns of a skin. The short-wave infra-red beams will penetrate into deeper layers of a skin; thus the sensation of heat is less expressed, though the amazing effect can be stronger.

The hit of infra-red radiation in environment of an eye is in details investigated. The beams with length of a wave 1500 - 1700 nm achieve a cornea and forward chamber, shorter beams with length of a wave 1300 nm will penetrate up to crystal-line lens. The short infra-red beams pass through a brain environment and influence on receptors of a brain.

At a long irradiation by infra-red radiation temperature of a fabric easy, head brain, kidneys and muscles raises. The irradiation by infra-red beams influences biological activity of organism that first of all is reflected in a condition of phagocytal activity of leucocytes.

The most expressed adverse influence of infra-red radiation is observed in industrial conditions, where the capacity of radiation can many times over exceed a level of infra-red radiation in natural conditions. At working hot shops and others, having contact to powerful flows of infra-red radiation, the electrical sensitivity of an eye is lowered, the latent period of visual reaction is increased, the reflection reaction of vessels is weakens. Infra-red radiation at length of a wave less than 1400 nm causes heavy changes of a cornea as cataract. The similar adverse consequences are possible only at absence of appropriate protection and preventive measures. Therefore one of the important parties of activity of the sanitary doctor is the duly prevention of diseases connected to adverse influence of an environment.

Seen part of a solar spectrum

Except for a ultra-violet and infra-red spectrum, the sun carries a powerful flow of seen light.

The seen part of a solar spectrum occupies a range of waves from 400 up to 760 nm.

The day time light exposure on the open area depends on a condition of weather, character of a spreading surface, height of an arrangement of the sun above horizon. The average light exposure on months in an average strip of the Soviet Union changes over a wide range - from 65000 lk in July up to 4000 lk and less in December.

The dusting of air renders the expressed influence on size of day time light exposure. In large industrial cities natural light exposure on 30 - 40 % is less, than in areas with rather pure atmospheric air.

In time rising and call of the sun the horizontal light exposure makes about 1000 lk, after call of the sun the light exposure quickly falls.

The minimal light exposure is observed at the night. In night without the moon the light exposure is created at the expense of light of stars, absent-minded light of an atmosphere and own luminescence of the sky. The small share in general light exposure is made by light reflected from light terrestrial objects. The minimal light exposure, at which eye of the man is capable to distinguish subjects, makes 0,7-0,8 • 10-4 lk.

Seen light renders significant biological action. It is shown not only in specific influence on function of sight, but also in the certain influence on a functional condition of the central nervous system and through not ё on all bodies and systems of organism. The organism reacts not only to this or that degree of light exposure, but also on color scale of solar light.

In 1878 N.G.Vvedenskiy has noted raised excitement of frogs paw on the covered party. V.M.Bechterev in 1916 has established calming down action light-blue and stimulating action of red colour on the patients with mental frustration. N.F.Galanin specified change impellent chronaxia at irradiations of an animal by red, dark blue and violet light.

If impellent chronaxia at day time illumination to accept for 100 %, at illumination by red light chronaxia will make 71 %, dark blue - 142 %, violet - 156 %, and in darkness - 141 %.

C.V.Kravkov Observed change of force of compression of a hand depending on colours of illumination.

The special hygienic meaning of light consists in its influence on function of sight.

The basic functions of sight, which cause its productive work, are: an acuteness of sight, that means ability of an eye to distinguish two points as isolated at maximum small distance between them; contrast sensitivity, i.e. ability to distinguish bright nesses; speed of distinction determined by the minimal time of an establishment of size and the form of a detail; stability of clear vision, time-dependent clear vision of a subject. The physiological level of functions of sight in known limits is individual, but always find in known dependence on a level of light exposure, colour of a background and detail, size of working details etc.

At low light exposure quickly there comes visual exhaustion and the serviceability is reduced. For example, at 3-hour visual work and light exposure 30 - 50 lk the stability of clear vision is reduced on 37 %, and at light exposure. 100 - 200 lk only on 10 - 15 %. Therefore hygienic norm of levels of light exposure of workplaces is established according to physiological features of visual functions. The creation of a sufficient level of natural light exposure in premises has the large hygienic meaning.

In illumination of premises plays a role not only direct solar irradiation, but also absent-minded light from the sky and terrestrial surface.

Natural the illumination of premises depends on orientation of apertures on the countries of light. It is known, that the orientation of windows to the southern parties creates more high levels of light exposure and promotes longer insulation of premises in comparison with orientation to northern parties. At east orientation of windows the direct solar beams will penetrate into a premise at morning o'clock, at western orientation insulation is possible in second half of day.

The intensity of natural illumination of premises is influenced also by a degree of blackout of light by nearby buildings or green plantings. If through a window the sky is not looked through, the direct solar beams will not penetrate into a premise that results in illumination by absent-minded beams and worsens the sanitary characteristic of a premise.

The intensity of solar radiation inside premises always is less outside. At southern orientation the intensity of solar radiation indoors makes 25% outside, at other orientations it decreases even more essential.

On a window sill at an open window the intensity of a ultra-violet irradiation makes 60 % of total it in the street, in depth of a room on distance 1 m from a window ultra-violet radiation reduces for 25-20 %, and on distance 2 m does not exceed 2,3 % of ultra-violet radiation in the street.

Dense building of quarter a close arrangement of houses result in the even greater loss of solar radiation, including its ultra-violet part. The premises located in the bottom floors and to a lesser degree - premise of the top floors are most of all blacked out. The conditions of light exposure by natural light are influenced by some architectural factors: the design of apertures, presence of blacking out architectural details, colouring of walls of a building etc. The large meaning has cleanliness of glasses. The polluted glasses, at double glass reduce natural light exposure till 50-70%.

The modern construction of cities takes into account these factors. Correct orientation, free building, the large apertures for light, absence of blacking out details, light colouring of houses create favorable conditions for good natural light exposure of inhabited premises.

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